Process of treating by-product liquors from wood sulfite plants.



APPLICATION FILED NOV. 26, 1915. RENEWED NOV. 19.1917- C. MARCHAND, DECD.

M. L. MARCHAND, Anmlmsrmmlx. PROCESS OF TIREATING BY-PRODUCT LIQUORS FROM WOOD SULFITE PLANTS.

Patented Jan. 15, 19118.

l E @Alg PNTENT @hilltllttllilo 'rnrxor sain CHARLES MARCHAND, DECEASED, ASSIGNOR TO THE MARCHAND PROCESS COMPANY, CHICAGO, ILLINOIS, A CORPORATION F ILLINOIS.

PROCESS TREATING BY-PRO1DUCT LIQ'UORS FROM." WOOD SULFITE PLANTS.

Application lec November 26, 1915, Serial No.

To all whom t may concern:

Be it known that I, CHARLES MARCHAND, a citizen of the United States, residing at Portland, inthe county of Multnomah and State of Oregon, have invented certain new and useful Improvements in Processes of Treating By-Product Liquors from Wood Sulfite Plants; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same. Y

This invention relates to process of treating by-product liquors from wood-sultite plants, and has for an object to provide the more specific and detailed steps tor carrying into eect the process disclosed in latent No. 1155256, issued September 28, 1915, wherein a practical manufacturing and commercial process is provided.

The drawing is a diagrammatic view of an apparatus for carrying into effect the several steps ot' the present process, providing a tank l otany predetermined size into which the waste liquor from the wood-sulflte plant is run. "lhis tank l is composed of material not easily acted upon by sulfuric acid, as for instance, wood, and is preferably though not necessarily provided with an agitator 2 driven in-any approved manner as by the belt 3. 'lihe treatment of the by-productliquors in the :tant: l as disclosed in the atoresaid patent, beginning at line 53 and ending at line 63, causes a precipitation of calcium sulfatev SQa, as indicated at t, which calcium sulfate is drawn ed in any approved manner as through the gate 5 and forms a valuable fertilizer.

rom the tank l the liquor trom which the calcium sulfate has been precipitated is .drawn through the pipe 5 and through the :lter press t3 into the charge measurer and preliminary heater 7, the passage being through the pipe 8 controlled by the valve 9.'. The iilling ot the charge measurer 'l' to the predetermined height produces exactly the charge ot liquor required in the rst elect of the evaporating system, to be hereinafter described. YThe preliminary heating isV accomplished by means eta coil l0 receiving condensed steam from the heating box ll ot the tirst evaporator edect l2. lhe steam to the heating box ll is supplied Specification of Letters Patent.

`Patenured dan., 515, 312MB,

63,602. Renewed November 19, 1917. Serial No. 202,836.

through a pipe l3 from any usual and ordinary source oflsteam pressure and heat, and .after heating the evaporator eiiect l2 passes through the pipe 1 4 to the coil l0 ot the preliminary heater and is discharged iinally through the exhaust pipe l5. 'llhe liquor in the preliminary heater 7 is maintained at the temperature required for proper evaporation in the first evaporator e'ect, preferably trom 95 to 98 C. so that when being run into the tirst evaporator eect l2 through the pipe 3 6 is at the proper temperature so that .evaporation immediately takes place under the vacuum maintained therein. The vacuum in the evaporating edect l2 is maintained by means of the pipe l? running to the heating box 18ct the next evaporator atleet in the system shown at i9, and being therein condensed produces the vacuum in the eect L2 without mechanical means `for supporting or maintaining such vacuum.

'llo maintain a higher vacuum in the second evaporator eect 19, a pump 20 or other vacuum apparatus is employed. is shown, the vapor oi.2 evaporation passes from the second effect i9 `through the pipe to the column 22 which communicates through pipe 23 with the column 24 which in turn communicates through the pipe 25 directly with the pump 2O so that the vacuum produced by the pump 20 eects directly the evaporator eliect 19..

rlhe column 22 is provided with a plurality of battle platesl 26 in which is disposed quick-lime, as indicated at 27, so that as the vapor from the evaporator 19 passes downwardly through the column 22 it comes in contact with the lime supported upon the several battle plates 26. The lime so supported is hydrated and dripping over the edges ot' the battle plates tinally passes through the conduit 29 into the pit 30.

ln the meantime, the vapor from the evaporating effect l2 has passed through the pipe l? and heating box i3 where it has been reduced in volume by condensation, and from that heating box passes through the pipe 3l and one of the branches 32 or 33 to the tanks 34 'or 35 respectively. ln the tanks 3d and 35 an alkali as quick-lime, limestone, magnesia, or dolomite or-sodium carbonate is the A maintained as indicated at 36, which said i a i V fili densed vapor thereon, and is alternately drawn out through the discharge pipes 37 or 38 while the opposite tank is in operation. The column 24 is of the usual cascade condenser type having the bafiie plates 39 located therein and receiving cooling and condensing water from the pipe 40 which, passing down through the condensing column 24 and pipe 41, is finally discharged into the sewer 42 or to waste in any approved manner. It will be apparent that the vapors passing through the pipe 23 and up to the column 24 will be condensed therein so that the pump 20 will be drawing substantially dry air through the ipe 25, and will not be subjected to any o the injurious gases from the evaporator. The pump 20 is a-lso-provided with a pipe 42 which leads to a compression tank 43 connected with the charge measuring device 7 by means of the pipe 44, controlled by the valve 45 so that when it is desirable to charge the evaporator effect 12 from the preliminary heater 7 it is not necessary to rely wholly upon the vacuum or rarefaction within the evaporator effect 12, but air is supplied from the compression tank 43 to force the contents of the charge measurer from the tank 7 into the tank 12.

The final evaporation effect 19 is connected with a tank 46 by means of a pipe 47 in which tank 46 the oxidizing agent is added as described in the aforesaid patent, beginning at line 74 and ending at line 87.

To expedite the oxidization of the liquor an agitator 48 is preferably located in the tank, 46, driven in any approved manner as by the pulley 49. From the tank 46 the liquor free from all traces of sulfite is conducted through the pipe 50 to the fermentation tank 51 where the fermentation of the sugar is accomplished and from which distillation is carried out in any usual well-known manner.

It is to be understood that while but two of the evaporating effects 12 and 19 are shown in the drawings the number may be increased to any desired number 'to effect a more rapid and expeditious handling of the liquor, and that if other -evaporating tanks are provided they would be introduced between efi'ects 12 and 19 in so far as the temperature is maintained and'vacuum provided and also in regard to their heatlng and other `action in relation to the eyaporation effects as shown it being considered necessary here to show only the termmal effects, it being understood that intermedlate effects "may be added without affectingthe present invention.

The pipe 52 is also provided spanning the lnterval between the effects 12 and 19 controlled by ha valve through which the contents of one may pass to the other. The

pipe 53 is also provided communicating.

with the pipe 42 communicating with a coil 54 in the bottom of the tank 46 whereby air from the pump 20 may be employed to cool the contents of such tank 46. The pipe 53 is controlled by a valve 55, a valve 56 being also employed in the pipe 42 so that the air may be cutr offrom the compression tank 43 and passed through the pipe 53. y

In the present apparatus the process is carried out as follows.

The waste liquor from the wood-sulfite plant is first run into the tank 1 and is treated bythe sulfuric acid. The reaction between the sulfuric acid and the sulfites contained in the waste liquor will raise the temperature of such liquor contained in the tank 1 to some point between 90 and 100 C., usually from 95 to 98. After precipitating the calcium sulfate the liquor is passed through the filter press 6 into the charge measurer and preliminary heater 7 until the liquor has reached approximately the top of such charge measurer as indicated therein. The several evaporating effects are now filled with water and the necessary heat and vacuum applied. The production of vapor at the effect 12 when passed through the pipe 17 and condensed in the heating box 18 will produce a vacuum in the effect 12, and when such desired vacuum is accomplished the initial water in such effect is discharged and the heated charge in the measuring device 7 is charged therein by the application of air from the expansion tank 43. 1n the charge measuring device the liquor is maintained at atmospheric pressure or un er pressure higher than atmospheric press re, and at a temperature less than 100 C. preferably from 95 to 98 C. This liquor at this temperature is charged into the effect 12 and the heat thus secured is maintained therein by the heating box 11. The evaporating effect 12 is maintained under `about twelve (12) inches vacuum so that by maintaining the liquor at from 95 to 98 C. rapid evaporation is effected, the heated vapors passing through the pipe 17 and heating box 18 to heat the second effect 19.

After evaporation has been conducted in the first effect to evaporate a predetermined percentage of the sulfur d-ioXid and water, the water maintained in the evaporating effect 19 at approximately 7 5 C. and under twenty-seven (27) inches vacuum is discharged and the liquor from the evaporating effect charged thereinto through the pipe 52 by reason of the greater vacuum contained in the eect 19. As soon as the liquor from the effect 12 has been discharged into the effect 19, the effect 12 is recharged from the measuring device 7 which has been in turn recharged from the tank 1 while evaporation was taking place in the effect 12. At this aaaaeaa point evaporation is taking place in the effects 12 and 19 and preliminary heating taking effect in the preliminary heater 7, and the device is in complete operation. ln the last evaporating effect the sulfur. dioxid is so far evaporated that but a trace remains, and the liquor is discharged from such final evaporating effect through the pipe 47 into the tank 46, and there treated with the oxidizing agent. The sulfur dioXid evaporated from the effect l2 is combined with the alkali in the tanks 34 and 35 while the sulfur dioXid from the effect 19 is combined with the alkali in the column 22 and discharged into the pit 30, and the calcium sulite produced thereby is a ain employed in the usual manner in the sul te pulp process.

I claim;-

1. The process of treating by-product liquors from wood-sulfite plants consisting in maintaining such liquors in a tank, treating such liquors with sulfuric acid to convert the suliites into sulfates and precipitate the lime, discharging a predetermined quantity of the treated liquor into a preliminary heater and charge measurer, maintaining the liquor in such preliminary heater at a temperature under boiling, discharging the liquor from the preliminary heater into an evaporator, evaporating the liquor in such evaporator under-'vacuum to remove a port-V. tion of the sulfur dioXid, discharging the partially evaporated liquor into a subsequent evaporator, maintaining the liquor in such subsequent evaporator at a lower temperature and higher vacuum, evaporating the sulfur dioxid in such subsequent evaporator until the greater portion of the sulfur dioxid is vaporized, passing the vapor from such evaporators through a reagent to produce a sulfite, discharging the liquor from the iinal evaporator into a tank, treating the liquor in such last-mentioned tank with an oxidizing agentto'produce sulfuric acid, running the liquor carrying such sulfuric acid into a tank, and termenting such liquor.,

2. 'llhe process oiv treating by-product liquors from wood-sulite plants consisting in employing a series of vacuum evaporators and a preliminary heater, discharging the liquors successively from the preliminary heater throgh the several vacuum evaporators and treating it therein to temperatures decreased and vacuum increased with each step of its progress, the vapor from the several evaporators and passing it through lime, treating the residue from .the iinal evaporator with an oxidizing agent, and fermenting the liquor so treated.`

3. The process of treating by-product liquors from wood-sulte plants consisting in treating the liquors with surfuric acid to convert the sulites into sulfates and to raise the temperature of the liquors by such reaction, maintaining the liquor at such ternperature in a preliminary heater in successive charges, charging the liquor from the preliminary heater into a series of vacuum evaporators successively maintained at lower temperatures and higher vaccum, evaporating 0E the sulfur dioXid stopping short oi entire elimination until but a trace remains in the last evaporator, passing the vapor from each evaporator over a reagent to produce a sulte, passing the liquor from the final evaporator with its trace of sulfur dioxid into a tank, treating the liquor in such tank with an oxidizing agent to convert the sulfur dioxid into sulfuric acid, running the liquor containing such sulfuric acid into a tank, and fermenting.

In testimony whereof l aix my signature 1 CHARLES MARCHAND.

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